a. Technical Field
The instant disclosure relates generally to power electronics systems, and more particularly to an isolated AC/DC electric power conversion apparatus compatible with multi-phase (e.g., three-phase) and single-phase AC input power with improved power density.
b. Background
This background description is set forth below for the purpose of providing context only. Therefore, any aspects of this background description, to the extent that it does not otherwise qualify as prior art, is neither expressly nor impliedly admitted as prior art against the instant disclosure.
Isolated alternating current (AC)/direct current (DC) electric power converters can be used in many different applications. For example only, such an electric power converter can be used as a battery charger to charge a DC battery associated with an electric-motor powered automotive vehicle. Known isolated AC/DC electric power converters may adopt three main stages. For example, a typical configuration may be a half-bridge resonance based isolated AC/DC converter that includes (i) a first, converter stage configured to convert grid or mains AC voltage (e.g., 50 or 60 Hz) to an output DC voltage (to implement power factor correction) stored across a relative large capacitor, (ii) a second DC/AC converter stage configured to transform the rectified DC voltage to a relatively high-frequency AC voltage (e.g., hundreds of kHz) applied to an electrical isolation device—such as a transformer, and (iii) third AC/DC converter stage configured to rectify the high-frequency AC voltage signal to produce a final DC output voltage signal. A target battery may be arranged to receive the final DC output voltage signal. The 3-stage converter described above incorporates a relatively large, bulky DC capacitor, which can, among other things, reduce power density.
With the progress of electric vehicles, the demand for electric vehicle battery chargers is increasing. Due to different electric power grid standards in different countries, it would be desirable for such battery chargers to accommodate both three-phase AC input power (e.g., 400 VAC in Germany) as well as single-phase AC input power (e.g., 208 VAC in the United States). Such flexibility would shorten the product development period. Known dual-input power chargers (e.g., 3-phase, single-phase), however, exhibit relatively poor power density when operated with single-phase AC input power. For example, such a charger is purported to deliver ˜20 kW with three-phase AC input power, but drops to only ˜3.3 kW (or 6.6 KW based on the AC input) with single-phase AC input power.
It would be desirable to provide an AC/DC electric power conversion apparatus, such as battery charger, that is capable of being configured for use with either multi-phase (e.g., 3-phase) or single-phase AC input power and that exhibits improved power density when operated with single-phase AC input power.
The foregoing discussion is intended only to illustrate the present field and should not be taken as a disavowal of claim scope.